Apparatus for controlling fluidized beds

Abstract

An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

We claim: 
     
       1. In an apparatus for conduct of oxidation or gasification of solid carbonaceous particulates comprising a reaction vessel having a grate and an ash discharge conduit in its lower portion and a fluidized bed supported on said grate within said reactor, the improvement comprising: ash content measurement means extending into said fluidized bed within said reaction vessel and measuring ash content relative to carbon content of fluidized solid carbonaceous materials within said fluidized bed; an ash removal conduit extending through said reaction vessel and having an open end in communication with said fluidized bed and independent of said ash discharge conduit; ash removal valve means in said ash removal conduit to control removal of ash; and said measurement means comprising control means opening said ash removal valve means when said measurement means indicates ash content within said fluidized bed exceeding a first predetermined amount which is above a suitable ratio of ash to carbon and below the ash content at which sintering takes place and closing said ash removal valve means when said measurement means indicates ash content within said fluidized bed is reduced to a second predetermined amount which is below said suitable ratio of ash to carbon. 
     
     
       2. The apparatus of claim 1 wherein said control means further opens carbonaceous particulate inlet means providing increased flow of said carbonaceous particulates to said fluidized bed during said ash removal. 
     
     
       3. The apparatus of claim 2 wherein said ash discharge conduit is an ash agglomerating discharge conduit. 
     
     
       4. The apparatus of claim 1 wherein said ash discharge conduit is an ash agglomerating discharge conduit. 
     
     
       5. The apparatus of claim 1 wherein measurement means comprises means measuring pressure drop across a specified distance in said fluidized bed. 
     
     
       6. The apparatus of claim 3 wherein said ash agglomerating discharge conduit has gas flow means associated therewith for controlling agglomerate removal, said gas flow controlling means being independent of said ash removal conduit. 
     
     
       7. The apparatus of claim 4 wherein said ash agglomerating discharge conduit has gas flow means associated therewith for controlling agglomerate removal, said gas flow controlling means being independent of said ash removal conduit. 
     
     
       8. The apparatus of claim 1 wherein said ash removal conduit is in communication with lockhopper means for discharge of material at atmospheric pressure.